Portable communication devices, such as mobile phones, personal digital assistants (PDAs) and tablets have become extremely popular and for many users are now considered indispensable.
One of the most important components of portable communication devices (hereinafter referred to as “UE”s) are their antennas, which are configured to radiate and receive electromagnetic waves so as to transmit and exchange wireless information signals between the UE and other locations. Such antennas must be designed to work with multiple frequency bands such as those used in present day wireless communication networks. Wireless communication device users continue to demand increasingly thinner, lighter and miniaturized devices. Such demands place additional physical limitations on the antennas used in portable wireless communication devices. As a result, multi-band antenna design for mobile communication devices continues to become more complex.
The housings of portable communication devices or user equipment (UE) may accommodate one or more antennas that support wireless communications. A UE may use long-range wireless communication systems such as cellular telephone systems, to send and receive communications. Such cellular or other long-range wireless communication systems may include, the Global System for Mobile Communications (GSM) telephone bands, Enhanced Data rates for GSM Evolution (EDGE); General Packet Radio System (GPRS); CDMA, such as IS-95; CDMA2000; WCDMA or Universal Mobile Telecommunications System (UMTS); Fourth Generation Long Term Evolution (LTE); other wide area network communication systems; PrivateMobile Radio (PMR); Worldwide Interoperability for Microwave Access (WIMAX); WLAN; other 3G or 4G networks; or the like. UEs may also use short-range wireless communication protocols to support communications with nearby devices. Such short rang protocols may include Wi-Fi (IEEE 802.11) and Bluetooth protocols.
The positioning and placement of antennas in UEs having smaller and thinner housings present additional design challenges. Handheld communication devices have largely abandoned antenna designs that have an antenna projecting outward from the housing. Mobile communication device housings are now routinely designed with internal antenna elements. However, when antennas are positioned within or and along an edge of the device housing, the presence of a user's hand can degrade antenna performance. Regardless, antennas are routinely located along an inner edge of the device housing despite the increased likelihood of these detrimental effects.
Additionally, when an antenna is included as part of an exterior surface of a UE chassis, such as a metal band about the edge of the UE chassis, dropping the UE may result in damaging, bending, deforming or generally moving aspect of the antenna from its previous location to another location. Since these antennas are impedance tuned or matched with a transceiver of the UE in order to help maximize transmission power and reception of radio signals, a damaged, bent, deformed or antenna that is moved relative to other metal elements of the UE may result in a change impedance and/or capacitance of the antenna relative to the transceiver circuit that it has been matched or tuned to. As such, what is needed is a method and circuitry adapted to correct or rematch the impedance of a deformed metal band antenna with the transceiver related circuitry of the UE.